Research on population dynamics and biodemographic composites is very abundant in mammals, but bats are unfortunately poorly studied. Unfortunately, in addition to being threatened by habitat loss and degradation, bat populations of North America have recently been affected by the arrival of white nose syndrome (WNS), a disease caused by the fungus Pseudogymnoascus destructans that affects bats during hibernation. Since 2006, the syndrome has spread to 28 American states and 5 Canadian provinces, resulting in a decrease of 90 to 100% among populations. Because of the extinction risk faced by some American species, it is critical to increase our understanding of their life history traits, and how these traits influence the population dynamics of these species. This project have four major objectives and will examine aspects related to the demography, reproductive success, and reproductive energetic constraints facing Myotis species in regions with and without WNS. The first objective is to examine the distribution and demography of bats in Quebec based on data collected at maternity colonies in regions with and without WNS. We will determine if maternity count data reflects demographic changes that have been observed based on counts at hibernacula. Data for this objective will be collected mainly by citizen scientists helped by governmental biologists and different non-governmental organizations. This citizen science project was initiated in 2012 by the Ministère des Forêts, de la Faune et des Parcs, and was improved with a website (Chauve-souris aux abris/Neighbourhood Bat Watch) in 2014 in collaboration with the Quebec Centre for Biodiversity Science. Citizens can upload the location and counts of bats occupying maternity colonies during the spring-summer reproductive season. In Quebec, we now have more than 233 maternity and over 120 accounts registered on the website. Our second objective would involve a more detailed monitoring of certain maternity colonies in Quebec of little brown bat to estimate female reproductive success and return rates in areas with and without WNS. This objective also intends to identify energetic constraints associated with reproduction in these different areas. Return rate will be investigated for three years using catch and release data (obtained by pit tagging). Reproductive success will be evaluated based on lactation status and data on juveniles. We will determine an index of females’ body condition that will be linked to an index of relative daily torpor, group size and microclimate (ambient temperature and relative humidity). This will allow us to measure energetic constraints associated with reproduction. Data for this chapter will be collected in maternity colonies in Quebec, starting in 2016. The third objective is to effectively translate preferences of natural roosts to artificial bat house designs. Bat houses are frequently used as a conservation measure to increase bat roost habitat, often in cases when citizens have excluded bats from their dwellings. Conservation organizations have also started to encourage the installation of bat houses as a potential tool to combat WNS. However, only very few bat houses are colonized. Many studies reported that thermal properties and location are important factors for roost choice by female bats. Maternity colonies of bats generally inhabit warmer roosts close to feeding sites to reduce energetic costs. We propose to test a total of five pre-existing and new bat house designs based on a review of the preferences and requirements of the bats most impacted by WNS, little brown and Northern long-eared bats. We will evaluate the quality of the bat houses based on positioning and thermal abilities. Bat houses will be installed across Quebec. Our fourth objective is to see if citizen science can be used to provide data on bats that can be useful for conservation and management. This objective will involve the management, development, and expansion of our citizen science website we described above in objective one. In 2015, the website was also expanded to cover Ontario and Manitoba by researchers at the University of Winnipeg and discussions are currently underway with researchers in other Canadian provinces to expand the website to cover these regions for the 2017 bat reproductive season. The first step toward being able to use the data we have collected to inform conservation decisions is to validate the data that we have already collected. Through this process we will identify common mistakes and find ways to change the data entry process to avoid these errors. The next step for the website will be to develop new content and new activities to keep citizens engaged in the project. From a scientific perspective, this objective would lead to a chapter on the use of citizen science for the monitoring of endangered species.